1. Field of the Invention
The present invention is generally related to a throttle body assembly and, more particularly, to a block of material attached to a throttle plate for the purpose of reducing the sound generated by air passing through the throttle body structure.
2. Description of the Prior Art
Those skilled in the art of throttle bodies and, more particularly, throttle bodies used in marine propulsion systems are familiar with a problem that is inherent in certain throttle body structures. As air flows through the cylindrical conduit of a throttle body, past the throttle plate, sound is generated. This sound can be irritating to passengers on a marine vessel that is powered by the marine propulsion system. Those skilled in the art are also familiar with many different techniques used to address this problem of irritating noise and other forms of vibration relating to throttle bodies.
U.S. Pat. No. 6,647,956, which issued to Sharpton on Nov. 18, 2003, discloses a sound attenuating system for a marine engine. A sound attenuator is provided for an idle air control valve system in order to reduce noise emanating from the idle air control valve. The sound attenuator comprises a fibrous pad that is inserted into an air conduit of the idle air control system. In a preferred embodiment, the fibrous pad is inserted into the air conduit near the air inlet where the conduit receives air from a region upstream, or above the throttle plate. A small hole can be provided through the air inlet. In certain embodiments, the air inlet of the air conduit is an opening formed in an inner cylindrical surface of the throttle body. In alternative embodiments, the air inlet can be remote from the internal surface of the throttle body.
U.S. patent application Ser. No. 10/224,267, which was filed on Aug. 20, 2002 by Conley et al., disclosed a throttle plate having reduced air rush noise and method. A throttle body for use in the air intake system of a motor vehicle comprising a throttle body defining a throttle bore is described. The throttle plate is rotatably mounted within the throttle bore, having an outside diameter smaller than an inside diameter of the throttle bore. A plurality of fins, located on the throttle plate, extend from the throttle plate in a direction generally perpendicular to a plane defined by the throttle plate. The fins are optimized in number, thickness, spacing, length, shape, and angle to reduce air-rush noise without impacting engine performance.
U.S. patent application Ser. No. 10/104,232, which was filed on Mar. 22, 2002 by Elliott et al., describes a throttle plate wedge. A throttle plate assembly with a wedge for limiting air flow upon initial acceleration is described.
U.S. patent application Ser. No. 10/256,291, which was filed on Sep. 26, 2002 by Ha, describes a throttle apparatus. Air induction noise of a throttle apparatus caused by interference between flowing air and an opening for a bypass passage is reduced because a protrusion formed on an interior surface of the throttle apparatus changes aerodynamic features of the throttle apparatus.
U.S. Pat. No. 6,394,068, which issued to Palotay on May 28, 2002, describes a throttle shaft and plate assembly. A throttle assembly includes a throttle plate that is mounted for rotation with a throttle shaft. A first set of ribs is formed along a portion of the throttle shaft and a second set of ribs is formed along one side of the throttle plate. The throttle shaft includes a D-shaped boss that is received within a D-shaped opening in the throttle plate to properly locate the plate to the shaft. When the plate is properly positioned, the second set of ribs is positioned transversely with respect to the first set of ribs and abuts against the first set of ribs. Weld energy is supplied along the length of the rib interface to secure the plate to the shaft.
U.S. Pat. No. 6,602,099, which issued to Loberger et al. on Aug. 5, 2003, discloses a vibration isolation support structure for a throttle body. An isolation mounting system is provided for the purpose of supporting a throttle body structure which is completely supported by an elastomeric support, but is held in noncontact association with an air intake manifold in order to effectively isolate the throttle body structure from vibration. This isolation protects potentially delicate components contained within a component housing that is rigidly attached to the throttle body structure.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
As air rushes past the edge of a throttle plate, when the throttle plate is partially opened, annoying and irritating sounds can be generated. It would therefore be significantly beneficial if a simple and inexpensive method could be provided that is effective in reducing the overall magnitude of irritating noise emanating from a throttle body structure when air is flowing past a partially opened throttle plate.